Will stern tube grease melt bitumen?

[jenevers]

?

[Tracy D'arth]

Won't do it much good.  Some worse than others I suspect.

 

Are you thinking of greasing a motorway?

 

TD'

[Jen-in-Wellies]

If you set it on fire.

[Dr Bob]

Can't see why it would. You may get a little bit of leaching of some of the components of the bitumen but it wont melt it. What leaches out  shouldnt degrade the bitumen but might discolour the grease.

[jenevers]

I just wondered if it might have the same effect as diesel?

[Dr Bob]

1 minute ago, jenevers said:

I just wondered if it might have the same effect as diesel?

Diesel doesn't 'melt' bitumen, it dissolves some of the components. As grease is a solid it can't dissolve things but it can extract stuff but nowhere near as strong as a liquid would. Which bit of the boat are you worried about?

[Alan de Enfield]

8 minutes ago, Dr Bob said:

Which bit of the boat are you worried about?

Maybe - the bit with bitumen on it ?

 

But having deleted his OP he appears to be no longer concerned.

[Dr Bob]

2 minutes ago, Alan de Enfield said:

Maybe - the bit with bitumen on it ?

 

But having deleted his OP he appears to be no longer concerned.

He only ever had the ? In the first post. If you spread grease over the whole of the hull painted with bitumen then maybe it would weaken it a bit but the odd bit here and there would not be an issue. Just wondering where he was putting the grease. 

[jenevers]

58 minutes ago, Dr Bob said:

He only ever had the ? In the first post. If you spread grease over the whole of the hull painted with bitumen then maybe it would weaken it a bit but the odd bit here and there would not be an issue. Just wondering where he was putting the grease. 

The inside of my baseplate bilge has a few pits. So, having Vactanned and bitumened the Whole baseplate, I thought if I applied a blob of grease in each pit. It would prevent any moisture being held there.

 

[Dr Bob]

19 minutes ago, jenevers said:

The inside of my baseplate bilge has a few pits. So, having Vactanned and bitumened the Whole baseplate, I thought if I applied a blob of grease in each pit. It would prevent any moisture being held there.

 

The density of water is higher than organic grease so the water would still potentially get to the bottoms of the pits. You should be fine if you remove any water regularly. Moisture is not an issue. Water is more of an issue.

[BEngo]

I am not sure that a blob of grease over a pit is a good thing corrosion wise.  The grease will exclude oxygen, but there will still be moisture at the bottom of the pit, providing an anaerobic corrosion site. 

 

Rinse the bilge with diesel occasionally.  The space under my elderly and not always continent engine collects the odd oil and  diesel drips, as well as the water from the reciprocating water pump.  It gets mopped out about once a week and despite having little paint in places it has not gone rusty after 31 years.

 

N

[David Mack]

You can get proper barge grease to protect the inside of boat hulls.

 

Edited June 21, 2020 by David Mack

[jenevers]

3 hours ago, David Mack said:

You can get proper barge grease to protect the inside of boat hulls.

 

Bet antiroestvet is similar to stern grease. I believe old Dutch barges, treated with it from new, still have well preserved bilges.

[Bee]

The inside of our boat is painted with water tank paint, I am fairly sure this is bitumen based. The bitumen has virtually gone under the stern gland where various oily stuff and a bit of water gathers. It doesn't bother me very much as it is oily and unlikely to corrode badly.